This invention relates generally to an electromagnetic shutter release device for cameras and more particularly to an electromagnetic shutter release device having an armature adapted to slide in two steps relative to the yolk of an exposure control electromagnet and arranged to start exposure at the first step and to start aperture closing at the second step.
Up to the present time, it has been usual to provide a camera having an electric shutter which electrically controls exposure operation with an additional electromagnet for starting the exposure operation by electromagnetic release motion independently of an exposure control electromagnetic device. This duplicative provision of electromagnetic devices requires an increased number of parts and a complicated mechanism resulting in a costly device. On the other hand, a method employing a single electromagnetic device has been introduced. In this method, the exposure operation is started by the electromagnetic release while the armature is attracted to the yolk and kept in position when the electromagnetic device is energized, then the aperture closing operation is started after a fixed period of time by releasing the armature from the yolk by deenergizing the electromagnetic device. However, this method has a practical disadvantage that the electromagnetic device requires an intensive electric current to attract the armature to the yolk.